"Joining the Linux Foundation is one of many ways Valve is investing in the advancement of Linux gaming," Mike Sartain, a key member of the Linux team at Valve said. "Through these efforts we hope to contribute tools for developers building new experiences on Linux, compel hardware manufacturers to prioritize support for Linux, and ultimately deliver an elegant and open platform for Linux users."

Mark my words: Valve will do for Linux gaming what Android did for Linux mobile. Much crow will be eaten by naysayers in a few years.

Back in 2009~2010 the Linux kernel, and several other components of the GNU ecosystem, was all but suitable for mobile (even today it still do not sorted off his power management issues in laptops, just to give a idea), and with the tight schedules of product shipping these days, there was no time to play the politics required to adapt all components and push back the patches to community before using.

TomTom had been shipping plenty of mobile devices running Linux, and so did many other vendors, so this is large overstated.

Valve on other hand don't need to do any of that. The changes that Valve needs to to on Linux are minimal. His distro will be desktop oriented, all components needed for gaming development is already in place, and developing software on Linux these days is a bliss. The only thing lacking is a descent display server, but this is questionable. Perhaps better IDEs are needed, but this is a non-issue for many developers, more a matter of taste and development style.